The invention relates to the use of high explosives. To be more specific, this device relates directly to the safe initiation of multiple types of initiating cord presently in use today, carrying out the various blasting needs in mining operations, in building highways, dams, water and sewer systems, as well as in military applications, to name a few.
At the present time, there are three (3) known and widely used systems for initiating high explosives. The high explosives have been designed to be desensitized for obvious reasons, mainly to allow for manufacturing storage, transportation and handling safely without fear of premature detonation.
Two prime considerations when using high explosives are (1) placing the blaster a safe distance from the explosion to prevent injury from flyrock, flames, concussion, or a combination of the three, and (2) initiating the material which provides the safe distance (standoff) between the blaster and the blast. The standoff distance cannot be identified as a specific distance of measure and is therefore directly related to many blasting accidents.
Three primary methods of detonation available to the blaster to provide standoff distance: (1) electric blasting using wire and electric blasting caps (2) radio controlled blasting using communication telemetry and (3) initiation cord or tube. This patent applies to the electric and non electric method.
Using the initiation cord or tube method, sufficient energy must be available to reach the high explosive and to detonate the less sensitive yet largest volume of explosives which perform the work at the blast site.
One method of starting the initiation cord/tube is by an electric blasting cap, with the blaster initiating the cap by wire from a distance using a blasting machine. This technique is dangerous since the blasting cap contains much more high explosives than is necessary to start the initiation cord/tube, and blasting caps must be logistically accounted for under federal law. These caps are prone to radio frequency energy which can cause premature detonation.
Another method of starting initiation is a mechanical starter comprised of a shot shell primer coupled directly to the initiation "tube". This method is also dangerous as close proximity to the detonating cord can cause bodily injury because of its external burning rate of approximately 24,000 feet (7000 meters) per second. Despite this possibility of danger, the shot shell primer, which has far less dangerous effects than the electric blasting cap, has been proven to provide initiation effectively. Another drawback in using this technique, however, is the waste of initiation tube which can only be used one time and is then discarded. This can be expensive, if the minimal standoff distance is 1000 feet (300 meters) then 1000 feet of material must be gathered and discarded.
This invention combines two of the best methods of initiation, i.e., shot shell primer, a low intensity device, and reusable electric wire to provide a standoff distance far greater than nominal and may be used many times over. The capacitor discharge power supply serves both methods and initiates electric blasting caps using the conventional electric blasting techniques, the same standoff cable and the same housing which includes the non electric firing device as a junction box to provide electric blasting connections.